You're anxious for lush lawn, but go easy on fertilizer

Answered by Brad Fresenburg, turf specialist with MU Extension: My best advice is to not overdo it. Many homeowners who put fertilizer on their lawns every spring are rewarded with fast growth and a rich green color. But after that spurt of growth, an overfertilized lawn may be more vulnerable to disease and less able to withstand the stresses of heat, drought and pests.

Don't just make random applications of fertilizer without knowing what the nutrient needs of the lawn are. Soil testing tells the homeowner those nutrient needs. Soil tests are available through county MU Extension centers for a fee.

If you have thin spots in the lawn that you want to over-seed with new grass, do so by mid-March so seedlings are established in time to compete against weeds. To ensure good soil-seed contact, scratch up the surface with a garden rake or power rake to prepare a seedbed.

Then sprinkle the seed in that thin area and rake it in lightly.

Getting seedlings established early is especially important if you plan to combat weeds with a pre-emergent herbicide. Pre-emergents prevent seeds from germinating, and they generally don't discriminate between the seeds of weedy plants and those of the plants you're trying to grow.

If you can get at least one mowing on that new seedling grass, that's generally considered established enough to use a pre-emergent herbicide.

For proper timing of pre-emergents, soil temperature is the best indicator. Apply pre-emergent herbicides when soil temperatures reach 55 degrees on the surface for about five consecutive days.

You can determine this by pushing a thermometer into the top inch of soil.

If you let the soil dry slightly, a deeper and hardier root system will develop. Lawns with good root systems will need less water, leaving them better equipped to endure drought and less vulnerable to disease and insect pests.

Brown patches in your lawn don't necessarily mean the grass is thirsty. They could be a sign of disease, such as brown patch, a fungal blight common in tall fescue.

Fungi thrive when moisture and nitrogen are plentiful, so watering or fertilizing might make things worse.

Q: My neighbor and I have a bet about the best mowing height for our grass. I say higher is better. What do you advise?

Answered by Brad Fresenburg, turf specialist with MU Extension: You win! While some might be tempted to cut their grass short so they won't have to mow as often, letting grass grow higher creates a canopy that deprives upstart weeds of light and space.

Weeds are there because of a lack of competition from the lawn. If homeowners can maintain a healthy, dense lawn and mow at 3 1/2 to 4 inches, they can reduce summer annual weed populations as much as 80 percent without the use of a pre-emergent herbicide.

A corn gluten-based organic fertilizer can provide as much as 60 percent control of summer annual weeds, and in combination with the taller, dense lawn, homeowners can expect nearly 100 percent control.